Saw-guide for band-saw mills.



No. 676,708. Patented lune is, |9ol.

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SAW GUIDE FOR BAND SAW MILLS.`

(Application led Nov. 16, 1900.) '(No Model.) -2 Sheets-Sheet l.

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Patented Iune I8. I90ll. W. A. WILKINSON. l S'AW GUIDE FDR BAND SAW MILLS. (Application ld Noy. 16, 1900.)

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SAW-GUIDE FOR BAND-SAW MILLS.

SPEGXEIGATIQN forming part of Letters Patent No. 676,708, dated J une 18, 1901. Application filed November 16, 1900. Serial No. 36,653. (No model.)

My present invention relates to saw-guides for band-saw mills, and has for its object to improve the same in the several particulars hereinafter stated.

The invention consists of the novel devices and combinations of devices hereinafter described, and deined in the claims.

It may be here further stated that the function of a saw-guide of the character to which this invention relates is to hold the band-saw against lateral and torsional movement while at work on a log or other article being sawed. Such saw-guides, especially when applied to a band-saw mill intended for sawing logs, are usually made adjustable, so that they may be moved for action on the saw close to the log and regardless of the size of the log.

One feature of my invention is directed to an improved device in the nature of a directacting fluid-pressure engine which is controllable at will and the piston of which is connected to the saw-guide,whereby the said sawguide may with ease and rapidity be adjusted according to the size of the log which is to be sawed. To prevent these vsaw-'guides from being broken or torn from their supports in case they are struck by the log, they have hitherto been yieldingly mounted.

A very important feature of my invention resides in a novel device for mounting the saw-guide, whereby it will not only yield when l struck, but will rise vertically and move out of the path of the log, so that it cannot be struck or engaged by the log While the latter is making its return movement.

Still another feature consists in providing a latch, which is applied so as to latch or lock the guide in the highest position to which it may be forced or raised by the log. A pawland-ratchet device is the best form of the latch.

and partly in vertical section, some parts being broken away, illustrating a band-saw mill having my improved devices above indicated applied thereto. Fig. 2 shows the parts illustrated in Fig. l, partly in front elevation and partly in vertical section, some parts being broken awa-y. Fig. 3 is a detailed view, in rear elevation, some parts being broken away, showing a portion of the straight-line fluidpressure engine; and Fig. 4 is a detail in section, showing aportion of the distributionvalve and the valve-chest of the engine.

The numeral l indicates the bed-plate, the numeral 2 one of the supporting-columns, the numeral 3 the band-saw, the numeral 4 one of the saw Wheels or pulleys, the numeral 5 the log-carriage, and the numeral one of the table-rollers, of an ordinary band-saw mill.

The character a indicates the guide-shoe of the upper saw-guide, which is mounted to slide on a vertical guide 7 of the standard or column 2. This shoe a has a rigidly-secured and horizontally-projected shaft a', to the outer end of which in turn is rigidly secured a head a2. To the head a2 is pivoted a pair of depending links b b. The links b b eX- tend parallel and are of the same length. The saw-guidefis shown as made up of a pair of parallel and horizontally-extended straps, between and to the rear ends of which the links -b b are pivoted, as best shown in Fig. 2. At

the forward ends the straps f normally embrace the saw 3, and they may be provided, as is ordinary, with wearingplates for direct engagement with the sides of the saw. One of the links-as shown, the link b-has rigidly secured at its upper end a 'segmental ratchet b2. As shown, the ratchet h2 has ratchet-teeth which extend reversely from its central portion, so as to make the same reversible. For cooperation with the ratchet h2 a pawl b3, which, as shown, is gravity held, is pivoted to a lug or projection a3 of the head a2. Vith this construction if the log moving in the direction indicated by the arrow marked on Fig.,2 should engage the forward end ,"of the saw-guidef the said saw-guide will be moved rearward, and at the same time ICO under the action of the links b b' it will be gradually raised and always kept in a horizontal position. The pawl b3, by its engagement with the teeth of lthe ratchet b2, will hold the saw-guide fin the highest position into which it is forced by the log. By this means the saw-guide is positively held upward in such a position that it will not be engaged by the log when the log makes its return or reverse movement.

Of the parts of the straight-line engine or Huid-pressure motor, g indicates the cylinder, which is vertically disposed and rigidly secured to the bed-plate l, and g' indicates the piston, the stem g2 of which projects upward and is attached at g3 to a bracket d4 on the shoe d.. The distribution-valve g, which is of tubular form, is mounted to slide in a suitable seat g5, formed in the valvechest gf'. This valve g4 cooperates with admission-ports Q7 and exhaust-ports g8, which lead from the valve-seat g5 to the ends of the cylinder. Live steam or other motive fluid is admitted to one end of the valve-seat g5 through a pipe g, and the exhaust from the ports g8 passes first to an enlarged central portion g10 ot' the valveseat g5 and then outward through an exhaustpipe gm. When the distribution valve g4 stands in its intermediate position, (shown in Fig. 2,) live steam is cut 0E from both ends of the cylinder, and the piston g' will not be forced in either direction, but will be left standing where set. Vhen the distributionvalve is moved upward, the lower admissionport Q7 and the upper exhaust-port g8 will be open, with the obvious result that the piston g', shoe a, and saw-guide f will be moved upward. When the said valve is moved downward, it is of course evident that a reverse `action will take place and the said piston lsaw-guide, with intermediate parts, will be moved downward. To readily actuate the valve g4, a pivoted hand-lever Q12 is pivoted to a suitable support Q13, and a projection thereof is connected by a stem 914 to the said valve g4.

It is desirable that the valve g4 assume its vintermediate position (indicated in Fig. 2) automatically whenever the lever Q12 is released.

VHence the said valve is provided with a projecting stem Q15, which works through the upper end of a bracket gw, (shown as secured on the upper cylinder-head.) On the stem Q15, one above and one below the upper end of the bracket gli", is a pair of coiled springs Q17, compressed between the said bracket and adjustable collars g1S on the said stem. The centering-springs g17 when properly set neutralize when the valve g4 is in its normal intermediate position. (lndicated in Fig. 2.) The one spring or the other may of course be readily overcome by means of the lever Q12; but whenever the said lever is released the distribution-valve will, by the said springs, be centered or thrown to its intermediate normal position, in which position, as already indicated, the saw-guide will be left standing in whatever position, with respect to vertical adjustments, it may be set.

The guide-shoe a, saw-guide f, and parts movable therewith are advisably counterpoised, so that they will have no tendency to move from any vertical position in which they may be set. In Fig. l a rope k, which at one end would run over a suitable guide and be provided with a weight or counterpoise, (not shown,) is shown as connected at its other end to a collar 7c' on the shaft d' of the shoe d.

The advantages of the several features of construction above set forth are thought to have been made clear by the foregoing description. It may, however, be added that the application of the straight-line engine directly as a means for raising and lowering the saw-guide permits the same to be moved from one position to the other with much greater rapidity and ease than with devices hitherto used for the same purpose.

lt will of course be understood that the saw-guide having been struck by a log and forced into its retracted position is released and reset by the operator, the pawl b3 having been raised out of engagement with the teeth of the ratchet b2.

A retracted position of the saw-guide is illustrated by dotted lines in Fig. 2. Another advantage afforded by the adjustment of the saw-guide always in a horizontal position is that the said guide maybe projected onto the saw more or less for proper action on a saw of any width or face and will always be left in a horizontal operative position. It is also desirable to call attention to the fact that when the links Z9 b and saw-guide f are set as shown by full lines in Fig. 2 the downward strain on the end of the guide, due to friction, will be transmitted to the said links b b' in direct line with their pivotal centers, so that there is little or no tendency to force the guide rearward or in its retracted position under the action of the saw itself.

It will of course be understood that the device shown in the drawings is capable of many modifications withinv the scope of my invention.

l/Vhat l claim, and desire to secure by Letters Patent of the United States, is as followsf Al. The combination of a saw, of a saw-guide yieldingly mounted for movement into an inoperative position, and an automatic lock for said guide, permitting the same to move into an inoperative position, and then operating to hold the same in such inoperative position, substantially as described.

2. The combination with a saw, of a sawguide, a yielding support for said guide, and a pawl-and-ratchet device operating automatically as a latch, to positively hold the said saw-guide in its retracted position, substantially as described.

3. The combination with a saw, of a sawguide, a pair of parallel pivoted links supporting said saw-guide for receiving movement always in a horizontal position, and a IOC) IIO

pawl-and-ratchet device operating automatieally to hold the said links and saw-guide in their retracted positions, substantially as described.

4. The combination with a saw, of a head or support, the pair of parallel links b b pivoted to Said support, the one having the ratchet b2, the pawl b3 pivoted to said support and cooperating automatically with said ratchet, and the sa\v-gnide f pivoted to the lower ends of said links ZJ b, for receding movement, always in a horizontal position, substantially as described.

5. In a band-saw mill, the combination with a vertically-adjustable saw-guide, of a straight-line or direct-acting engine, operating the same, said engine having a distribution-valve, which is operative at will, and a yielding device arranged for action on said Y VILLIAM A. WILKINSON.

vWitnesses:

M. M. McGRoRY, F. D. MERCHANT. 

